they just kept insisting, but I just did it today, so I can change. It is an extra $135 but in the overall expense, it is Really nothing. I was just looking at appearance. I keep coming back to 2 and really should go back to that, if for no other reason that it will be tough putting 2 dursos in one overflow

Well if you are having the the tank built. Ok hold on. Are we talking built in overflows or overflow boxes. Here is what i would do if it were me since it is a big tank.

I would do two built in overflows or have the tank drilled. I would then have two or three or even four returns. One at each end of the tank and maybe two twards the middle. That will give you alot of flow. Of course you will have to have one heck of a pump. But it would be pretty awesome. That is what i would do if i had the money to get such an awesome tank.